The present invention relates to a thermal cycler and a DNA amplifier method for amplifying nucleic acid of the DNA.
In the case of inspecting how nucleic acid (gene) in a gene-recombinated crop influences on the human body or in the case of inspecting gene of a patient, the nucleic acid in the crop or nucleic acid particular to the patient must be extracted from respective individual. However, in order to provide nucleic acid of an amount necessary for inspection, extracted nucleic acid must be amplified and there is PCR (polymerase chain reaction) method as the amplifying method. The PCR method is featured in being highly accurate and highly reliable in order to directly analyze gene with less influence by heat.
According to PCR method known as a method of amplifying efficiently such a small amount of DNA (Deoxyribonucleic acid), one cycle is constituted by a step of denaturing DNA by maintaining a micro tube holding DNA at inside thereof at a temperature of around 95xc2x0 C., a step of annealing DNA by maintaining DNA at a temperature of around 55xc2x0 C. and a step of amplifying DNA by maintaining DNA at a temperature around 70xc2x0 C. and DNA is amplified by repeating the cycle (refer to U.S. Pat. No. 4,683,202). In carrying out the PCR method, it is important to use an apparatus capable of controlling temperature with high accuracy since an efficiency of amplifying DNA is increased by accurately controlling the thermal cycle of the respective steps.
Further, as another amplifying method, there is known NASBA method in which nucleic acid is amplified at a constant temperature of 50 through 60xc2x0 C.
However, highly accurate temperature control is needed even in NASBA method.
FIG. 1 shows a conventional example of thermal cycler which is an apparatus for automatically carrying out PCR method.
The thermal cycler is provided with a metal block 101 inserted with micro tubes 100, wells 102, a heater 103 and a cooling pipe 104.
The micro tubes 100 including a sample are inserted to the wells 102 engraved to the metal block 101 comprising aluminum and in the metal block 101, temperature of the micro tubes 100 is controlled by using the heater 103 and the cooling pipe 104 to thereby amplify DNA of the sample.
Normally, the wells 102 are formed at about one hundred portions in the metal block 101 and the micro tubes 100 of about one hundred pieces, are simultaneously processed.
Further, when DNA used for research is amplified, the kind of DNA is previously specified and therefore, an amount of about several microliters is sufficient, however, when unknown DNA used for inspection is amplified, an amount of about several milliliters is needed. Thereby, an enormous time period is taken for amplifying DNA to a desired amount.
However, in the above-described conventional apparatus, all of the micro tubes 100 of about one hundred pieces are simultaneously heated or cooled by the heater 103 and the cooling pipe 104 and therefore, it is difficult to uniformly control temperature. This is because temperature of the inserted micro tubes 100 (sample) is controlled by heating or cooling the metal block 101 inserted with the plurality of micro tubes 100. Therefore, there is a concern that temperature of the micro tubes 100 becomes nonuniform depending on positions of the metal block 101 and there is a possibility that an amount of product after reaction differs by the respective micro tubes 100 and becomes incomplete.
Further, individually different temperature control cannot be carried out for the respective micro tubes 100 and accordingly, for example, even when one hundred pieces thereof can be processed simultaneously, when the processing is started by inserting only ten pieces of the micro tubes 100 to be processed into the wells 102, the processing efficiency is lowered. Further, there poses a problem in which when the processing is on standby until one hundred pieces of the micro tubes 100 have been prepared, a time period of processing is increased.
Hence, the present invention has been carried out in view of the above-described conventional problem and it is an object of the present invention to provide a thermal cycler and a DNA amplifier in which highly accurate temperature control can be carried out with regard to individual micro tubes and the processing efficiency is promoted.
In order to achieve the above-described object, according to an aspect of the present invention, there is provided a thermal cycler comprising a plurality of wells capable of containing micro tubes holding a sample including nucleic acid, a plurality of heaters provided at the respective wells for directly or indirectly heating the micro tubes, a plurality of temperature sensors measuring temperature of the micro tubes, and a control apparatus inputted with measured values of the temperature sensors, supplying current to the plurality of heaters based on the measured values and controlling the temperature of the respective micro tubes independently from each other.
According to another aspect of the present invention, there is provided a thermal cycler comprising a plurality of wells capable of containing micro tubes holding a sample including nucleic acid, a plurality of nozzles provided at the respective wells jetting a medium to the wells, a plurality of heaters provided in the nozzles heating the medium, a plurality of temperature sensors measuring temperature of the micro tubes, and a control apparatus inputted with measured values of the temperature sensors, supplying current to the heaters based on the measured values and controlling the temperature of the respective micro tubes independently from each other.
According to another aspect of the present invention, there is provided a thermal cycler comprising a plurality of cylindrical wells which are capable of containing micro tubes holding a sample including nucleic acid, one end portion of each of which is formed with an opening portion for inserting the micro tube and other end portions of which constitute bottom portions, a plurality of temperature sensors installed in contact with outer walls of the wells measuring temperature of the micro tubes, a plurality of heaters arranged to surround the outer walls of the wells or proximately thereto heating the micro tubes, a case which is a case including a well chamber and an air chamber partitioned by a partition wall and in which the well chamber is arranged to align with the plurality of wells by protruding the opening portions of the wells to an outer side thereof and the outer walls of the wells having the temperature sensors to an inner side thereof and the air chamber includes a plurality of air fans, a plurality of cooling nozzles which are nozzles for cooling the micro tubes by jetting air to the wells, attached to be opposed to the bottom portions of the wells at positions of the partition wall in correspondence with the respective wells jetting air from the air chamber to the wells in the well chamber, and a control apparatus connected to the heaters, supplying current to the heaters in accordance with outputs of the temperature sensors controlling the temperature of the respective micro tubes independently from each other.
According to another aspect of the present invention, there is provided a thermal cycler comprising a plurality of wells capable of containing micro tubes holding a sample including nucleic acid and pasted with an indicator which differs in accordance with the respective sample, a plurality of pick up sensors detecting the indicator, a plurality of heaters provided at the respective wells directly or indirectly heating the micro tubes, a plurality of temperature sensors measuring temperature of the micro tubes, and a control apparatus inputted with measured values of the temperature sensors, supplying current to the heaters based on the measured values and controlling the temperature of the respective micro tubes independently from each other by a previously stored temperature pattern in correspondence with the indicator.
According to another aspect of the present invention, there is provided a DNA amplifier method having a control apparatus for controlling to heat a plurality of micro tubes holding a sample including nucleic acid independently from each other by a plurality of heat apparatus provided at the respective micro tubes based on measured values of a plurality of temperature sensors provided at the respective micro tubes and storing a temperature pattern heating the micro tubes, the DNA amplifier method comprising a step of reading the temperature pattern set for the respective micro tubes by the control apparatus, a step of generating a signal operating the heat apparatus based on the measured values and the temperature pattern by the control apparatus, a step of inputting the generated signal to the respective heat apparatus, heating the micro tubes independently from each other based on the signal by the heat apparatus and having a desired reaction carry out in the micro tubes, and a step of outputting a signal stopping operation of the heat apparatus to the heat apparatus based on the temperature pattern by the control apparatus.
According to another aspect of the present invention, there is provided a DNA amplifier method having a control apparatus controlling to heat a plurality of micro tubes for holding a sample including nucleic acid and pasted with an indicator which differs in accordance with the respective sample independently from each other by a plurality of heat apparatus provided at the respective micro tubes based on measured values of a plurality of temperature sensors provided at the respective micro tubes and storing a temperature pattern heating the micro tubes, the DNA amplifier method comprising a step of detecting the indicator and setting the temperature pattern in correspondence with the detected indicator by the control apparatus, a step of generating a signal operating the heat apparatus based on the measured values and the temperature pattern by the control apparatus, a step of inputting the generated signal to the respective heat apparatus, heating the micro tubes independently from each other based on the signal by the heat apparatus and having a desired reaction carry out in the micro tubes, and a step of outputting a signal for stopping operation of the heat apparatus to the heat apparatus based on the temperature pattern by the control apparatus.